(CNN) -- Drew Peterson may be fighting to keep what his missing wife and slain ex-wife allegedly said about him out of his murder trial, but he's always had plenty to say about the case.

Peterson, 56, has been charged with the murder of third wife Kathleen Savio. The charges came amid an investigation into the disappearance of his fourth wife, Stacy. He has pleaded not guilty to murder and denied involvement in Stacy's disappearance.

In court, Peterson has kept a low profile as some 40 witnesses have testified during pretrial hearings.

But in the past, the former police sergeant from Bolingbrook, Illinois, has spoken many of times to CNN's "Larry King Live," NBC's "Today Show," Fox News, the "Dr. Phil" show and local media outlets.

A critical part of his trial, now the subject of a month of hearings, hinges upon whether hearsay evidence can be used against him. Hearsay involves statements heard by third parties and jurors are rarely allowed to consider them because the original speaker can't be cross-examined.

Stacy Peterson and Savio both told others that they feared Drew Peterson and felt that their lives were threatened by him, according to testimony at the hearings. The defense is fighting to keep those statements, and others, out of his murder trial.

I got the bling. Can't complain.--Drew Peterson, on perp walk

Peterson maintained his style of police humor, even after he was charged with Savio's 2004 murder. As he was escorted from the jail to the courthouse for his arraignment in May, he snapped his gum and made wisecracks.

Asked how he was doing, Peterson quipped: "Three squares a day and a spiffy outfit."

And I got the bling," he added, holding up his shackles. "Can't complain."

Peterson calls himself "comical." But his behavior has dismayed the families of Savio and his missing fourth wife, Stacy. Some people accuse him of being authoritarian, smug and narcissistic. At times, his comments have hardly seemed to be those of a worried spouse whose wife is missing, critics say.

"He's an idiot," Savio's sister, Susan Doman, said in May on "Good Morning America," in reference to some of Peterson's jokes.

Investigators began looking at Peterson in October 2007 when Stacy, then 23, vanished. According to Peterson, his young wife dumped him for another man.

He appeared on NBC's "Today Show" about a month after her disappearance. When anchor Matt Lauer questioned him about their relationship, he responded, "I'm not trying to be funny here, but Stacy Peterson would ask me for a divorce after her sister died on a regular basis, and it was based on her menstrual cycle."

Stacy Peterson would ask me for a divorce ... on a regular basis, and it was based on her menstrual cycle.--Drew Peterson to NBC

But Peterson was in tears during a December 2007 interview on NBC's Dateline. This time, the topic was his children.

"I just want to be there for them," he said.

In Peterson's defense, his attorneys say that many of his more controversial comments have been provoked by journalists looking for sensational sound bites.

Camera crews swarmed his suburban Illinois home after his wife's disappearance. They descended on him early in the morning and were so loud they disturbed his family, Peterson has said.

In the midst of the media frenzy in 2008, Peterson turned his own hand-held mini-video camera on news crews. "I'm going to camp myself in front of your house and see how you like it," he said with a wide smile.

Also in 2008, Peterson planned on participating in a contest on Chicago's WJMK-FM radio station: "Win a Date with Drew Peterson." The station eventually canceled the contest.

A defensive Peterson appeared on Phil McGraw's daytime talk show to explain himself in November 2008. He attributed his gallows humor to a reaction to a difficult situation: He had gone from a happily married man to a single father, he said. He added that humor is his coping mechanism, as it is for many police officers.

When people look at me and say, 'You did this to your wife,' I look at them and laugh.--Peterson, to Dr. Phil

"When people look at me and say, 'You did this to your wife,' I look at them and laugh," Peterson said. "I say, 'Thank you, go screw yourself.' I normally have a smart-ass remark for people like that."

Then a month later came his reported engagement to a young woman who would have been the fifth Mrs. Drew Peterson. The engagement to Christina Raines, then 24, was called off after just a few weeks.

Meanwhile, prosecutors continued building their case. They re-examined the death of Savio, who was found naked in an empty bathtub. Although the initial autopsy found that her death was accidental, the state's second examination pointed to lacerations and bruises on her body. Authorities concluded that her death was homicide.

The evidence prosecutors have gathered against Peterson is largely circumstantial. No physical evidence or witnesses link Peterson to the crime, Peterson's attorney, Joel Brodsky has said. Brodsky has often appeared alongside Peterson on the numerous media appearances.

"He wanted to proclaim his innocence," Brodsky aid. "He had nothing to hide. He didn't feel like he should jut go into a dark corner," he added, explaining Peterson's many media appearances.

As for his client's demeanor, "He likes being out. He likes the people, he likes the interaction. His humor has always been his personality."

There is no book written on how I'm supposed to act.--Peterson. to NBC's "Today Show"

Peterson has argued many times that he was unfairly portrayed by the media -- and prematurely found guilty in the court of public opinion.

"There is no book written on how I'm supposed to act," he said in May in a phone call from jail with NBC's "Today Show." "Would it be better if I hid my head down hunched over and had tears in my eyes?"

And later that month, he was back on a Chicago radio show, joking about the jail's food and bathrooms.

"Hey, Mancow," Peterson teased host Mancow Muller. "I know we can't do the date with Drew. I'm thinking we should do 'Win a conjugal visit with Drew.' "

His remarks caused Will County Judge Stephen White to limit Peterson's contacts with the media last spring. Now he can call only a list of family members, friends and his attorneys.

Joe Hosey, author of "Fatal Vows: The Tragic Wives of Sergeant Drew Peterson," has been attending the pretrial hearings that began last month. Peterson has been speaking only to his attorneys. He's not smiling and laughing like before.